efficiency of centrifugal pump vs positive displacement|characteristics of positive displacement pump

A boiler feedwater pump is a specific type of pump used to pump feedwater into a steam boiler. The water may be freshly supplied or returning condensate produced as a result of the condensation of the steam produced by the boiler. These pumps are normally high pressure units that take suction from a condensate return system and can be of the centrifugal pump type or positive displacement type.

When it comes to pumping fluids in various industrial applications, two common types of pumps are often used: centrifugal pumps and positive displacement pumps. Each type has its own set of advantages and disadvantages, making them suitable for different scenarios. One key difference between the two is in their operating principles.

Positive displacement pumps are able to handle variations in pressure, flow and viscosity and remain efficient, unlike centrifugal pumps which do not operate well off the centre of their curve.

Centrifugal pumps work based on the principle of centrifugal force, where a rotating impeller increases the fluid's velocity, creating a flow of liquid. On the other hand, positive displacement pumps operate by trapping a fixed amount of fluid and then forcing it into the discharge pipe. This fundamental difference in operation leads to distinct characteristics and efficiencies for each type of pump.

Positive Displacement Pump Disadvantages

Positive displacement pumps offer several advantages, such as the ability to handle variations in pressure, flow, and viscosity efficiently. However, they also come with certain disadvantages that need to be considered. One of the main drawbacks of positive displacement pumps is their limited capacity for handling solids and abrasive materials. The design of these pumps can be easily compromised by the presence of solid particles in the fluid, leading to increased wear and reduced efficiency over time.

Additionally, positive displacement pumps can be more prone to leakage compared to centrifugal pumps. The tight clearances required for these pumps to operate efficiently can result in leakage issues, especially when dealing with high-viscosity fluids. This can lead to maintenance challenges and increased operational costs in the long run.

Positive Displacement Pump vs Diaphragm

One specific type of positive displacement pump is the diaphragm pump, which utilizes a flexible diaphragm to create a pumping action. Diaphragm pumps offer several advantages over traditional positive displacement pumps, including the ability to handle highly viscous fluids and solids more effectively. The diaphragm design also provides better containment for hazardous or corrosive fluids, making them suitable for a wide range of applications in various industries.

However, diaphragm pumps also have their limitations. They can be more prone to mechanical failures due to the repetitive flexing of the diaphragm, which can lead to increased maintenance requirements. Additionally, diaphragm pumps may not be as energy-efficient as other types of positive displacement pumps, making them less cost-effective in certain applications.

Characteristics of Positive Displacement Pump

Positive displacement pumps have several key characteristics that set them apart from centrifugal pumps. One of the main features of positive displacement pumps is their ability to maintain a consistent flow rate regardless of changes in pressure or viscosity. This makes them ideal for applications where precise control over flow is required, such as in dosing or metering systems.

Another characteristic of positive displacement pumps is their self-priming capability, allowing them to create a vacuum and draw fluid into the pump without the need for external priming. This feature makes positive displacement pumps suitable for applications where the pump may be located above the fluid level or where suction lift is required.

Positive Displacement Pump Working Principle

The working principle of a positive displacement pump involves trapping a fixed volume of fluid in a chamber and then displacing it into the discharge pipe. This process is repeated continuously to create a steady flow of liquid. Positive displacement pumps can be classified into various types based on their mechanism of operation, such as rotary pumps, reciprocating pumps, and diaphragm pumps.

In a rotary positive displacement pump, such as a gear pump or a screw pump, fluid is trapped between rotating elements and the pump casing, creating a pumping action. Reciprocating positive displacement pumps, like piston pumps or plunger pumps, use a piston or plunger to push the fluid through the pump chamber. Diaphragm pumps, on the other hand, utilize a flexible diaphragm to create a pulsating pumping action.

Centrifugal Pump vs Submersible

Centrifugal pumps and submersible pumps are both commonly used in various industrial and municipal applications for pumping water, wastewater, and other fluids. While centrifugal pumps are designed to be installed above the fluid level and use an impeller to create a flow of liquid, submersible pumps are designed to be submerged in the fluid and use a sealed motor to drive the pump.

One key advantage of submersible pumps is their ability to operate quietly and efficiently, as they are submerged in the fluid and do not require priming. They are also suitable for applications where space is limited, as they can be installed directly in the fluid without the need for external piping. However, submersible pumps may require more frequent maintenance compared to centrifugal pumps due to their submerged nature.

Centrifugal Pump vs Rotary

When comparing centrifugal pumps to rotary pumps, it's important to note that centrifugal pumps use a rotating impeller to create a flow of liquid, while rotary pumps trap fluid between rotating elements and the pump casing. This fundamental difference in operation leads to distinct performance characteristics for each type of pump.

Centrifugal pumps are known for their high flow rates and relatively low pressure capabilities, making them suitable for applications where a continuous flow of liquid is required. On the other hand, rotary pumps, such as gear pumps or screw pumps, offer higher pressure capabilities and are more suitable for applications where precise control over flow and pressure is needed.

Positive Displacement Diaphragm Pump

A positive displacement diaphragm pump combines the characteristics of a positive displacement pump with the design of a diaphragm pump. This type of pump utilizes a flexible diaphragm to create a pulsating pumping action, trapping and displacing a fixed volume of fluid with each cycle. Positive displacement diaphragm pumps are commonly used in applications where precise metering or dosing of fluids is required.

Understanding pump curves, such as the positive displacement pump curve vs centrifugal pump curve, and matching the pump’s performance to the specific needs of …

Suitable for vertical and horizontal installation. BB1 Type Pump. Between bearing 1 type, Horizontal and one-stage or two-stage pump. Axially split type. . Diagram Centrifugal Pump .It is one of the simple and exciting topics in fluid mechanics.What is the need for a pump? We require a pump to transmit water from a region of low pressure to a region of higher pressure. The centrifugal pump defines as a hydraulic machine that converts mechanical energy into hydraulic energyby means of a . See more

efficiency of centrifugal pump vs positive displacement|characteristics of positive displacement pump